Device for tensioning an annular sawblade

ABSTRACT

A device for tensioning in a radial direction an annular sawblade contained in an assembly comprising a plurality of annular rings. The sawblade is retained in the assembly by a mount ring, a tension ring and a lock ring. The assembly is fixed in position in the device by means of the mount ring. The tension ring is coupled to a torque-producing means whereby, when the tension ring is rotated relative to the mount and lock rings, an annular extension on the tension ring will be moved axially and into engagement with the surface of the sawblade. The force applied to the surface of the sawblade by the annular extension will cause an annular deformation in the form of a rib to be produced which results in the sawblade being tensioned in a radial direction.

United States Patent Bender et a1.

1151 3,678,917 1 51 July 25,1972

[s4] DEVICE FOR TENSIONING AN 1,812,816 6/1931 Weaver ..s1/57.39 ANNULAR SAWBLADE 3,324,539 6/1967 Cleland ..l/l5 X 1,778,055 10 1930 Al d r ..81 54 [72] Inventors: David L. Bender, Henrietta; Richard L. m e Lane Penfield both of Primary Examiner-Harold D. Whitehead [73] Assignee: Kayex Corporation, Rochester, NY. A rn y-Lloyd F ach [22] Filed: Oct. 12, 1970 [57] ABSTRACT [21] Appl 79812 A device for tensioning in a radial direction an annular saw- Relamd Application Dam blade contained in an assembly comprising a plurality of annular rings. The sawblade is retained in the assembly by a mount Commuanon-ln-pan of 809,498 March ring, a tension ring and a lock ring. The assembly is fixed in 19691 abandonedposition in the device by means of the mount ring. The tension ring is coupled to a torque-producing means whereby, when "125/ the tension ring is rotated relative to the mount and lock rings,

an annular extension on the tension ring will be moved axially [58] Field ofSearch ..8i/57.39, 29/406, 125/155i 1723, and into engagement with the: Surface of the sawblade. The force applied to the surface of the sawblade by the annular ex- 56 R f C1 d tension will cause an annular deformation in the form of a rib 1 e erences I e to be produced which results in the sawblade being tensioned UNITED STATES PATENTS in "idle! dlrecum 3,247,837 4/1966 Wiseman 125/15 5 Claims, 4 Drawing figures 52 53 55 I H h 57 ll 48 l L, ,1 5 a 1 11 t .7 -5/ 54 j 47' 24 24 67 66 4 a 6/ 1: i ,4/ s2 v M, 35 l I: 2 i 9 I: f

2 Shuts-Sheet 1 Patented July 25, 1972 Patented July 25, 1972 2 Sheets-Sheet 2 I NVENTORS A GE N T DAV/0 L. BEA DER R/CHARD L. LANE mmm mlim X F i: 3 Q Q DEVICE FOR TENSIONING AN ANNULAR SAWBLADE This is a continuation-in-part of U.S. Pat. application Ser. No. 809,498, filed Mar. 24, 1969, in the name of David L. Bender and entitled DEVICE FOR TENSIONING AN AN- NULAR SAWBLADE and now abandoned.

FIELD OF THE INVENTION The present invention relates to a device for tensioning an annular sawblade in a radial direction and, more particularly, to a device which lends itself to such tensioning by the application of a uniform force to sawblades of various diameters.

DESCRIPTION OF THE PRIOR ART In the field of electronics various types of crystals are used as transistor and rectifier elements. These crystals, which are generally cylindrical in shape, are cut into thin wafers or slices 7 and then processed to obtain a wafer of a desired thickness.

Such crystals are very hard and brittle and for this reason annular sawblades having a diamond dust cutting edge are used to cut the crystal into wafers. However, in order to obtain wafers having surfaces of maximum smoothness and of a thickness that does not vary over the width or diameter of the wafer, it is necessary that the sawblade be tensioned in a radial direction to obtain the best cutting action.

In instances where the sawblades are relatively small in diameter, the radial tensioning can be accomplished by manual means, such as by use of a spanner wrench. However, as the size of the blade increases, the force required to obtain the desired radial tension becomes prohibitive from the standpoint of being accomplished manually and, further, cannot be accomplished so as to produce a uniform radial tension throughout the sawblade.

In addition, as the size of the blade increases in diameter, the size of the rings and the size of the threads on the rings also increase. As is well known, threads must be cut with a tolerance to permit easy turning of one threaded member relative to another. This tolerance also increases to a degree as the threaded diameter and size of the threads increase. In the present application, it was found that the torque applied directly to the threaded lock or mount ring caused the ring being turned to ride high on the other ring so that an uneven pressure was being applied to the sawblade. Although this pressure difference might be small and, hence, seem to be of no real significance, it was responsible for producing such a difference in radial tension of the sawblade, that uneven cutting of the wafers occurred as well as a cutting action that was less smooth. This difference in radial tension can be generally eliminated by rotatably mounting a spanner member on a center post and engaging the ring to be moved axially through the medium of spaced and accurately located pins which are carried by the spanner member and to which the torque is to be applied. In this way a high degree of concentricity can be maintained between the rings and the spanner member with substantially no thread runout. Consequently, the radial tension applied to the sawblade will be very uniform and the resulting cut will produce a wafer having much smoother surfaces. In addition, with more accurate centering of the sawblade, the cutting life of the sawblade will also be increased.

SUMMARY OF THE INVENTION The primary object of the invention is to provide a device for tensioning annular sawblades in a radial direction in which a uniform force can be applied continually to the sawblade in order to obtain a more uniform tension.

Another object of the invention is to provide a device for tensioning a sawblade in a radial direction in which the force applied to the sawblade is uniform and can'be applied continuously or continually in repeated steps or increments to obtain the desired radial tension.

Yet another object of the invention is to provide a device for tensioning sawblades in a radial direction in which the device can be used to tension sawblades of various diameters.

These and other objects and advantages of the invention will be apparent to those skilled in the art by the description which follows of a preferred embodiment of the invention.

The objects of the invention are attained by mounting an assembly of rings by which a sawblade is contained relative to a member which will provide a uniform torque to a movable member of the assembly. More specifically, the sawblade is mounted between a pair of rings comprising a mount ring and a lock ring. A tension ring threadably engages the mount ring and is provided with an annular extension for engaging a surface of the sawblade, the annular extension being aligned with and complementary in shape to an annular recess in the lock ring. The mount ring is fixed in position on the device and an actuating means in the form of a continuous, slow speed source, or a hydraulically operated piston, is operatively coupled or connected to a centered and movable spanner member which engages the threaded tension ring of the assembly through the mediumof drive pins, so that a uniform torque is applied to the tension ring with little, if any, thread run-out for moving the tension ring in an axial direction, the annular extension being moved axially against the sawblade and toward the recess in the lock ring. With this arrangement of the rings and such an actuating means, a high degree of concentricity is maintained and the annular extension exerts a uniform force against the sawblade in a direction perpendicular to the surface thereof, thereby uniformly tensioning the sawblade in a radial direction. The amount of radial tension can be controlled by the distance that the tension ring is moved in an axial direction. Also, with this arrangement, the speed of the actuating means in terms of the rpm or the operating pressure applied to the hydraulically operated piston can be used to control the rate at which the radial tension is applied.

DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings wherein like reference numerals designate like parts and wherein:

FIG. 1 is a plan view of the device showing the arrangement of the sawblade assembly to the torque-producing means and the hydraulic system for operating such torque-producing means;

FIG. 2 is a partial vertical sectional view taken substantially along the line 22 of FIG. 1 and showing the assembly of rings for mounting the sawblade;

FIG. 3 is a side elevational view of the device shown in FIG. I; and

FIG. 4 is a partial vertical sectional view, similar to FIG. 2 and showing another embodiment of the invention in which a continuous torque-producing means is coupled to the ring assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT and clamped between a lock ring 13 and a mount ring 14 by means of a plurality of screws or bolts 15 which pass through appropriate holes in the sawblade 10. The lock ring 13 is provided with an annular recess 16 over which the sawblade l0 lies when first clamped between rings 13 and 14. The crosssectional shape of recess 16 can be best seen in FIG. 2. The mount ring 14 is provided with an internally threaded opening 17 which threadably engages the peripherally threaded portion 18 on a tension ring 19. As best shown in FIG. 2, the tension ring 19 is provided with an annular extension 20 which is generally complementary in shape to that of recess 16 and at least a pair of diametrically spaced, blind holes 21. The mount ring 14 is provided with a flange 22 by which ring 14 can be secured in the cutting apparatus, or in this particular case, to the spacers 24 on the bedplate 25 of the device as will be described in more detail hereinafter.

When rings 13, 14 and 19 are assembled with the sawblade 10, the extension 20 is normally in engagement with a surface 26 of sawblade 10. It can be readily appreciated, when ring 19 is rotated in a direction such that it is moved axially toward lock ring 13, an annular and perpendicular force will be applied to surface .26 of sawblade by extension such that the sawblade will be forced into recess 16 so as to provide an annular ring, the shape and size of which wi-I be determined by recess 16 and extension 20. As the annular ring is formed, a stress in a radial direction is developed which effectively tensions the sawblade 10 in a radial direction. The extent to which the recess 16 and extension 20 deform the blade 10 will be dependent on the radial tension required. Consequently, with one blade .the depth or height of the annular ring or deformation will be a minimum, whereas with another blade it will be a maximum. This deformation is obtained by mounting the assembly of rings 13, 14 and 19 and sawblade 10 in the device generally designated by the numeral 30 and now to be described.

The device 30 comprises the bedplate 25 which can be mounted on any suitable supporting structure, such as that designated by the numeral 32 in FIG. 3. A plurality of fixed spacers 24 are arranged on bedplate 25 and positioned so as to receive the flange 22 of mount ring 14 which can be secured to spacers 24 by screws 34. Since lock ring 13 is secured to mount ring 14 by screws 15, both rings are thus held against rotation on bedplate 25 for the purpose described hereinafter.

Centering means comprising a post 35 and a spanner member 36, which carries at least a pair of diametrically spaced and extending pins 37, is arranged centrally of the ring assembly 13, 14 and 19 and sawblade 10. Post 35 is secured to bedplate 25 by screws 38 and has a portion 39 that is engaged by the central bore 40 in spanner member 36. The peripheral surface of spanner member 36 is provided with equiangularly spaced, axial notches or slots 41. After the assembly of rings 13, 14 and 19 and sawblade 10 has been placed on spacers 24 and secured by screws 34, the spanner member 36 is then placed on post 35 with the pins 37 thereon engaging the holes 21 in tension ring 19. The fit between the various parts is such that the threaded portions of rings 14 and 19 are centered with a minimum of, if any, eccentricity or thread runout. As a result, the rotation of spanner member 36 willv not cause any run out in the threaded portion 17 and 18 and, hence, there is and can be no change in the relationship of the parts due to the engagement of member 36 with post 35.

An actuating means comprises with other elements to be described an oscillatable ring which is freely rotatable on the surface 46 of mount ring 14 and with respect to spanner member 36, see FIG. 3. On a flat portion 47 of the ring 45, see FIG. 1, a bracket 48 is secured thereto and extends radially therefrom for connection toa hydraulically operated member 49. The bracket 48 includes a radially mounted ratchet member 50 that is urged toward the notches 41 on member 36 by a tension spring 51. The bracket 48 is pivotally connected by a threaded knob 52 to a clevis 53 that threadably engages at 54 the protruding end of a shaft 55 that is part of a piston (not shown) which is the movable (operating) portion of member 49. The member 49 is pivotally coupled at 57 to a suitable bracket 58 that is mounted on bedplate 25, thereby permitting the pivotal connection between bracket 48 and clevis 53 to be made without provision for any other movement of either member.

With the mount ring 14 secured to the spacers 24, the spanner member 36 in position over the tension ring 19 and the ring 45 in position, the ratchet member 50 will then be able to engage one of the notches 41 and the bracket 48 will be-in an extended position to the left, as shown by the dotted line position shown in FIG. 2. Upon actuation of the member 49, the shaft 55 will be moved to the right and this linear motion will be converted to rotation of the ring 45 through the pivotal connection between bracket 48 and clevis 53. This rotary motion turns spanner member 36 due to the engagement of ratchet member 50 with one of notches 41 and by means of pins 37 rotates tension ring 19 so it moves in an axial direction toward the sawblade 10. As a result, extension 20 is also moved in an axial direction and urges the portion of sawblade 10 directly thereunder into recess 16 causing a deformation to be formed and thereby radially tensioning sawblade 10. This movement of extension 20 is relatively slow and, depending on the amount of radial tension desired, the deformation can be relatively shallow or fairly deep. Since the movement of shaft 55 and, hence, the bracket 48, is limited by the stroke of the piston, it may be necessary to return the ring 45 and bracket 48 to their original position for engaging the next slot 41 and then continue rotation of the tension ring 19 until the desired radial tension is applied to sawblade 10.

In view of the description thus far, it is evident that the spacers 24 and screws 34 comprise means for receiving and holding the mount ring 14 against movement, whereas spanner member 36 comprises an engaging means. Also, the bracket 48 and ratchet member 50 comprise means for coupling the ring 45 to the hydraulic member 49, all of which might be considered as an actuating means for exerting the force necessary to radially tension the sawblade l0.

In the embodiment of theinvention described hereinabove, the hydraulic member 49 is preferably one that is actuated by means of a liquid, such as oil, but need not be limited to this particular type because a pneumatically operated member can also be used. In this arrangement a motor 60 drives a pump 61 through a coupling 62, the pump 61 circulating the hydraulic I medium through the desired path to actuate the member 49 (piston) in the required, direction. As shown in FIG. 3, a reservoir 63 for a hydraulic medium is located below bedplate 25 and the pump 61 moves the medium through a flow restriction valve 64 and then to a four-way valve 65. The-valve 64 determines the amount or volume of medium to be used, and is adjustable by means of knob 69, thereby controlling the rate at which hydraulic medium is pumped via line 66 to member 49 to move the piston and shaft 55 to the left as seen in FIG. 1 or whether the hydraulic medium is pumped via line 67 to the other end of member 49 so that the shaft 55 is moved to the right. A dial 68 is also interconnected into the system to indicate the pressure under which the hydraulic medium is operating.

A plurality of switches are arranged on the front of the bedplate 25, the switches 70 and 71 being used to actuate valve 64 so as to control the direction in which the piston of member 49 will be moved.

While the operating medium in the above-described embodiment is a hydraulic system using oil, an air-operated system can be used in substantially the same way. It will also be apparent to one skilled in the art that the assembly of rings 13, 14 and 19 together with sawblade 10 can be mounted relative to one another in other ways to efiect radial tensioning of the sawblade. In other words, the device described hereinabove can and will operate in substantially the same manner with other arrangements of the parts comprising the assembly for the sawblade that is to be radially tensioned.

With respect to the embodiment of the invention disclosed in FIG. 4, the sawblade I0 is mounted and clamped between a lock ring 13 and a mount ring 14 as described above with respect to FIG. 1. Also, the tension ring 19 threadably engages the mount ring 14 and the assembly of rings l3, l4 and 19 with sawblade 10 is mounted on the spacers 24 which, in turn, are mounted on bedplate 25. A shaft is rotatably mounted in bearing sleeves 91 and 92 which are secured to respective surfaces of bedplate 25. At the lower end 93, shaft 90 has a gear 94 fixed thereto by a pin or other suitable means, said gear being operatively coupled, as indicated by the dotted line 95, to a gear reducer 96 associated with a motor 97. The upper end 98 of shaft 90 is provided with a keyway 99 and is adapted to receive a spanner member 100 which is provided with at least a pair of diametrically opposite pins 101. When the member 100 is placed on the end 98 of shaft 90, that is, after the rings 13, 14, 19 have been mounted on spacers 24, the pins 101 will engage the holes 21 in tension ring 19 and the key 102 will make the spanner member 100 integral with shaft 90 so it will be rotated therewith. As described above, the centering of spanner member 100 on shaft 90, eliminates any eccentricity and/or thread run-out.

The speed of motor 97 is diminished by speed reducer 96 to the extent that shaft 90 is rotated at a very slow speed thereby providing continuous rotation of shaft 90 and member 100. If necessary an adjustable torque clutch can be inserted between gear 94 and reducer 96 (line 95) so as to limit the torque applied to ring 19, thereby controlling the radial tension actually applied to the sawblade 10. The connection between motor 97 and shaft 90 can be effected in many ways, as will be obvious to one skilled in the art, to provide the requisite torque for radially tensioning the sawblade by moving the annular extension against the sawblade 10. In this embodiment of the invention, the spanner member 100 and its pins 101 can be considered as an engaging means operatively coupled to motor 97 through the intermediate members, such as shaft 90, gear 94, etc., all of which taken together comprise an actuating means for radially tensioning the sawblade.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We Claim:

1. A device for tensioning in a radial direction an annular sawblade clamped between a first ring engaging one surface of said sawblade and an axially aligned second ring engaging the other surface of said sawblade and having an annular recess facing said other surface, said first ring threadably engaging a third ring having an annular extension aligned with said recess and engaging said one surface, said sawblade and said rings being arranged relative to a common axis, the combination comprising: I

means for receiving and holding said first and second rings against rotational and axial movement;

means rotatable relative to said common axis and operatively coupled to said third ring for applying a torque thereto;

centering means aligned with said common axis and supporting said rotatable means for rotatable and axial movement relative to said third ring so as to generally preclude any eccentricity between said first ring and said third ring when the latter is rotated and moved toward said sawblade; and

actuating means operatively coupled to said rotatable means for rotating the latter, whereby said third ring is rotated and said extension is moved against said one surface with uniform pressure to create an annular deformation in said sawblade and radially tension the same.

2. The device in accordance with claim 1 wherein said third ring is provided with a number of holes arranged equiangularly and radially about said common axis in the surface thereof opposite said extension and said rotatable means includes a corresponding number of drive pins extending therefrom for engaging said holes.

3. The device in accordance with claim 2 wherein said centering means comprises a post axially aligned with said common axis for maintaining said rotatable means concentric with said third ring, whereby said extension is moved relative to and against the one surface of said sawblade with generally uniform pressure.

4. The device in accordance with claim 1 wherein said rotatable means is provided with a plurality of equiangularly spaced, peripheral notches and said actuating means includes a ratchet drive ring having means for releasably engaging one of said notches and reciprocative means pivotally connected to said drive ring for rotating the latter and said rotatable means, when moved in one direction, and for rotating only said drive ring, when moved in the other direction, unti another one of said notches is releasably engaged by said drive l'ln 5% The device in accordance with claim 4 wherein said reciprocative means comprises a fluid-operated member pivotally mounted at one end and pivotally connected to said drive ring at the other end. 

1. A device for tensioning in a radial direction an annular sawblade clamped between a first ring engaging one surface of said sawblade and an axially aligned second ring engaging the other surface of said sawblade and having an annular recess facing said other surface, said first ring threadably engaging a third ring having an annular extension aligned with said recess and engaging said one surface, said sawblade and said rings being arraNged relative to a common axis, the combination comprising: means for receiving and holding said first and second rings against rotational and axial movement; means rotatable relative to said common axis and operatively coupled to said third ring for applying a torque thereto; centering means aligned with said common axis and supporting said rotatable means for rotatable and axial movement relative to said third ring so as to generally preclude any eccentricity between said first ring and said third ring when the latter is rotated and moved toward said sawblade; and actuating means operatively coupled to said rotatable means for rotating the latter, whereby said third ring is rotated and said extension is moved against said one surface with uniform pressure to create an annular deformation in said sawblade and radially tension the same.
 2. The device in accordance with claim 1 wherein said third ring is provided with a number of holes arranged equiangularly and radially about said common axis in the surface thereof opposite said extension and said rotatable means includes a corresponding number of drive pins extending therefrom for engaging said holes.
 3. The device in accordance with claim 2 wherein said centering means comprises a post axially aligned with said common axis for maintaining said rotatable means concentric with said third ring, whereby said extension is moved relative to and against the one surface of said sawblade with generally uniform pressure.
 4. The device in accordance with claim 1 wherein said rotatable means is provided with a plurality of equiangularly spaced, peripheral notches and said actuating means includes a ratchet drive ring having means for releasably engaging one of said notches and reciprocative means pivotally connected to said drive ring for rotating the latter and said rotatable means, when moved in one direction, and for rotating only said drive ring, when moved in the other direction, until another one of said notches is releasably engaged by said drive ring.
 5. The device in accordance with claim 4 wherein said reciprocative means comprises a fluid-operated member pivotally mounted at one end and pivotally connected to said drive ring at the other end. 